Use a stick to "escort" him off the trail and continue. Being a resident of the desert, I always PLAN on meeting up with one therefore am always cautious and very deliberate with each step. Just don't become complacent and you shouldn't have a problem. Also, if I know I'm going to be walking in waist high grass, I take a trekking pole to move the grass before I step. A stick would work just a good though...